3.7.3.1 The Processor and it's Components.

Question 1

What do processors contain?

Answer 1

ALU.
Control Unit.
Numerous Registers.

Question 2

Define an ALU.

Answer 2

Performs arithmetic and logic operation.

E.g. addition or XOR.

Question 3

Define Control Unit.

Answer 3

Controls the various components of the processor.

Controlling the fetch-execute cycle.

Question 4

Define a Register.

Answer 4

Small storage locations use to hold data temporarily.

Question 5

Define a Program Counter (register).

Answer 5

Used to hold the memory address of the next

instruction to be executed in the fetch-execute cycle.

Question 6

Define a Current Instruction (register).

Answer 6

Holds the instruction that is currently being executed

by the processor.

Question 7

Define a memory address register.

Answer 7

) Stores the memory address of a memory location

that is to be read from or written to.

Question 8

Define a status register.

Answer 8

Contains a number of bits, the values of which can

change to indicate the occurrence of an interrupt.

Question 9

Outline the role of the clock.

Answer 9

The system clock generates a timing signal which changes at a regular frequency. This signal is used to synchronise the communication between the components of the processer and the rest of the computer system.

Question 10

Outline the components of the cpu

Answer 10

Processor
System bus
I/O controllers
Main memory

Question 11

Processor purpose

Answer 11

To control different types of devices

Question 12

Processor components

Answer 12

Control unit
ALU
registers

Question 13

Control unit purpose

Answer 13

Managing all computer operations through the fde cycle

Question 14

Fetch

Answer 14

Instruction is fetched from main memory

Question 15

Decode

Answer 15

Instruction is broken into opcode and ooerand - may also send signals into the ALU

Question 16

Execute

Answer 16

Execute the instruction

Question 17

Registers definition

Answer 17

Special memory cells which operate at very high speed - used by arithmetic and logic operations.

Question 18

3 parts of the system bus

Answer 18

Address bus
Control bus
Data bus

Question 19

System bus definition

Answer 19

Connects all components in the computer using wires on the motherboard

Question 20

Data bus definition

Answer 20

Bi directional bus used to transport data and instructions between the three components of the three bus model.

Question 21

Is the data bus single or bi directional

Answer 21

Bi directional

Question 22

How many wires does a data bus usually have

Answer 22

32

Question 23

Effect of a larger data bus

Answer 23

Larger the data bus the more data that can be transported at one time

Question 24

Width of the data bus

Answer 24

Is a key factor in determining the overall system performance

Question 25

Adress bus definition

Answer 25

Bus that carries signals from cpu to main memory and I/O devices

Question 26

Adress bus single or bi directional

Answer 26

Single

Question 27

Memory is divided into

Answer 27

Units called words.

Question 28

Typical size of a word

Answer 28

8,16,32

Or 64 bits in size

Question 29

What happens when a cpu requests data from main memory

Answer 29

Send the address of the word to main memory via the address bus, then main memory returns the data along the data bus.

Question 30

Example in assembly code: LDA 23

Answer 30

this code would be sent from the cpu along the address bus.

Data at memory location 23 would fhen be sent back to the cpu via the data bus

Question 31

Width of address bus

Answer 31

Address bus of 3 bits (3 wires) then you would only have 8 different addressable blocks of memory.
(2^8)

Question 32

How to calculate memory.

Answer 32

2^n

Question 33

Control bus - bi or single directional

Answer 33

Bi directional

Question 34

Number of wires in control bus

Answer 34

More than 16

Question 35

Control bus definition

Answer 35

Used to transport control signals and instructions between thre components of the three box model. Such as when a device has finished a job or has just been plugged in

Question 36

Main memory definition

Answer 36

Store program instructions and data - the only data store that can be directly accessed from the cpu

Question 37

Simplest part of the computer in the priciple of the main memory

Answer 37

IAS (immediate access store)

Question 38

Main memory is made up of

Answer 38

RAM chips but can include one of more ROM chips

Question 39

Von nuemann machine

Answer 39

Data and instructions are saved in main memory.
Instructions sent to the processor via the system bus.
I/O is performed by IO devices.
Data travels from the I/O devices to the processor and main memory via the system bus.

Question 40

Stored program definition.

Answer 40

Program must be resident in main memory to be executed,

Machine code instructions are fetched from main memory one at a time, decoded and executed in the processor.

Question 41

Harvard architecture machine defintion

Answer 41

Has a seperate store for data and instructions.
Throughput is faster since there are faster since there are seperate stores for data and instructsionsnans seperate buses to connect them to the processor.

Question 42

Memory consists of

Answer 42

Data stored in addresses.

Question 43

The more main memory

Answer 43

The more addresses youll have

Question 44

RAM defintion

Answer 44

Used for readable and writable memory. Used by the processor to store (write) and load (read) data.

Question 45

ROM purpose

Answer 45

To find and load the first lines of code for the operating system.

Question 46

Modern CPU’s have

Answer 46

Internal memory (cache) and I/O devices have the ability to access memory without the need for the CPU, the address bus has go be bi-directional. However, the exam will treat it as uni-directal.

Question 47

Some modern systems combine

Answer 47

Combine address and data buses since they are used at different parts of the fde cycle.

Question 48

ROM nowadays is

Answer 48

Hard to write flash memory

Question 49

Flash memory requires

Answer 49

Special equipment, voltages od processes.

Question 50

Flash memory read only or write and read

Answer 50

Isnt true read only as you can change it with some difficulty e.g. if you havent updated your bios.